Apparatus for continuous mixing of solid and liquid material and extrusion of the mixture



March 3, 1970 c. F. FISCHER 3,497,912

APPARATUS FOR OONTINOUS MIXING OF SOLID AND LIQUID MATERIAL ANDEXTRUSION OF THE MIXTURE Filed Nov. 26, 1965 2 Sheets-Sheet 1 INVENTOR.Charles F Fischer awhw C. E FISCHER March 3, 1970 APPARATUS FORCONTINOUS MIXING OF SOLID AND LIQUID MATERIAL AND EXTRUSION OF THEMIXTURE 2 Sheets-Sheet 2 Filed Nov. 26, 1965 INVENTOR. Charles F F/ h r1 flri'aA/e FIG. /5

United States Patent 3,497,912 APPARATUS FOR CONTHNUOUS MIXING F SOLIDAND LIQUID MATERIAL AND EX- TRUSIQN OF THE MIXTURE Charles FrederickFischer, Jersey City, N.J., assignor to Colgate-Palmolive Company, NewYork, N.Y., a corporation of Delaware Filed Nov. 26, 1965, Ser. No.509,803 Int. Cl. B29f 3/02 U.S. (ll. 18-2 7 Claims ABSTRAET OF THEDISCLOSURE Continuous formation of extruded *built synthetic laundrydetergent bar by mixing and shearing the ingredients in a zone having aseries of successive counter-rotating paired paddles, mounted on twoparallel horizontal shafts; and extruding the mixture from said zone.The apparatus may have an extrusion passageway offset from the centralplane of the device.

This invention relates to a process for the production of syntheticdetergent laundry bars and to machinery particularly suitable forproducing such bars.

One aspect of this invention relates to a modification of a twin-shaftpaddle type mixing apparatus to enable the apparatus to be used not onlyas a mixing and intensive shearing apparatus, but also for a continuousmixing, shearing and extrusion operation in the manufacture of syntheticdetergent laundry bars containing high proportions of builder salts. Ithas been found, in accordance with this aspect of the invention, that byproviding a bar-discharge passageway which is offset with respect to thecentral plane between the twin shafts, it is possible to produceextrudates of smoother cross-section and closer grain and more uniformgrain structure across the width of the extruded bar, and to make goodproducts at high rates of production.

In one preferred embodiment of the invention the material is extrudedfrom the apparatus in a direction transverse to the central planebetween the shafts. In another preferred embodiment, the material isextruded in a direction parallel to the central plane, preferablythrough an opening which is adjacent to that side of the apparatus wherethe motion of the tips of the mixing and shearing paddles has agenerally upward, rather than downward, component. It has been found,surprisingly, that the best extruded bars are obtained when thedischarge opening is located at that side.

Certain preferred embodiments of the invention are illustrated in theaccompanying drawing in which:

FIGURE 1 is an overall side view of the apparatus;

FIGURE 2 is a top view, in crosssection, with portions broken away,showing the arrangement of shafts, feed screw elements and paddles, andthe position of a side discharge opening;

FIGURES 3 to 7 constitute a sequence of end views, partly incross-section, showing successive positions of the paddles during therotation of the shaft;

FIGURE 8 is an end view of an advancing paddle;

FIGURE 9 is a top view showing the tip edge of an advancing paddle;

FIGURE 10 is a top view showing the tip edge of a non-advancing paddle;

FIGURE 11 is an end view, partly in cross-section, illustrating thepositions of adjacent paddles on their shafts;

FIGURE 12 is a view, in elevation, of an end plate, showing itseccentric discharge passageway;

FIGURE 13 is a side view, partly in section, showing ice the end plateof FIG. 12 in position on the end of the housing of the apparatus; and

FIGURE 14 is a top view, in cross-section, showing an arrangement inwhich screw flights are employed at the discharge end of the apparatus;

FIGURE 15 is a schematic end view showing the mixing and extrusionapparatus coupled with a conveying, cutting and pressing apparatus.

Referring now to FIG. 1 of the drawing, reference numeral 11 designatesa jacketed housing within which there are mounted a pair of parallelrotatable shafts 12 (FIG. 2) each extending horizontally the full lengthof the housing and each having mounted thereon, for rotation therewith,feed screw elements 13 and agitator elements or paddles 14. Thelongitudinal cavity within the housing is made up of two intersectingcircular cylindrical zones (as can be seen from the end view in FIG. 3)each such cylindrical zone being coaxial with the rotatable shaftsituated in said zone; there being a small radial clearance between theinner walls of the cavity and the outer peripheries of the paddles andfeed screw elements. There is an opening or hopper 16 at one end of thehousing, above the feed screw elements, for introducing, into the cavityof the housing, the solid materials to be processed. In one embodimentof the invention, these solid materials are finely divided builder saltstogether with finely divided synthetic anionic detergent; the water tobe blended with the solid ingredients to form a pasty mass is introducedunder pressure through an opening 17.

To provide access to the interior of the housing, the latter is made intwo sections, namely, a stationary lower half 18 and a removable upperhalf 19 which is firmly but detachably secured to the lower half in anysuitable manner, as by means of bolts 21 passing through matchingflanges 22 of these two halves of the housing. The upper half 19 has adownwardly depending ridge 22 (FIG. 3) conforming to the circularportions above their intersection, and the lower half has a similarupwardly projecting ridge 23.

The two shafts are adapted to be driven in the same direction by a drivemotor and gear arrangement 24 situated at one end of the housing. Thefeed screw elements on the shafts are of conventional helical type,suitably intermeshing in well-known fashion as the shafts rotate toadvance the material, supplied through the hopper .16, in an axialdirection towards the paddles.

The paddles 14 are arranged in matching pairs, the design being suchthat a tip 26 (FIG. 3) of one paddle of each pair is always moving inwiping relationship to an edge 27 of the other paddle of the pair duringthe continuous co-rotation of the shafts. In one particularlyadvantageous construction, the paddles of any pair are identical witheach other and mounted with their long axes LA (FIG. 4) at right angles,the edges 27 of each paddle being defined by equiradial symmetrical arcswhose centers 0 and O' are symmetrically situated on the prolongationsof the short axis SA of the paddle. These arcs are of greater radiusthan the radii of the cylindrical zones of the cavity in the housing. Aswill be seen from the sequence shown in FIGS. 3 to 7, during thecorotation of the shafts about the rotational axes RA, one tip 26 of theleft hand paddle follows along the edge of flank 27 of the right handpaddle, and then a tip of the right hand paddle moves in identicalfashion along the edge of the left hand paddle. Thus, FIG. 4 is a viewafter a 45 rotation from the position shown in FIG. 3, and FIG. 5 showsthe relationship after an additional 67 /2 of rotation. After a totalrotation of from. the osition shown in FIG. 4, the tip of the right handpaddle is adjacent to the other tip of the left paddle, as

shown in FIG. 6. Thereafter, that tip of the left hand paddle moves inan identical fashion along an edge or flank of the right hand paddle;FIG. 7 shows the relationship after an additional 45 rotation. Thus, ina full 360 rotation, each edge of each paddle will be wiped once by atip of its matching paddle. During this full 360 rotation, the internalWalls of the housing will be wiped twice by the tips of the paddles.

Certain paddles 14 (hereinafter called advancing paddles) are designedto advance the material longitudinal- 1y of the shafts. T this end, theprofile of the rear face 31 (FIG. 8) of the advancing paddle is offsetby a slight angle a (about the axis of rotation) from the profile of itsfront face 32. For example, for a paddle having its long axis 4% incheslong and its short axis 2 inches long, and having a thickness of 1 inch,the two faces may be offset by an angle of 12 /2 The other paddle of thesame pair has the profiles of its faces similarly offset by theidentical angle, the design being such that the edge of each paddle willbe wiped by the tip of its paired paddle, as previously described. Thus,in any cross section through the pair of paddles, at right angles to theaxis of rotation, the relationship of the cross-sectional profiles willbe the same as that shown in FIGS. 3 to 7. To advance the material fromthe hopper end of the housing toward its opposite end, the profile atthe rear face of the paddle (that is the face nearest the hopper end) ispreferably offset (from the profile at its front face) in the samedirection as the direction of rotation of the paddles illustrated by thearrows in FIG. 8. It will be appreciated that while the tips are shownas being relatively sharp in the drawings, they may be relatively blunt,for example having arcuate tips as indicated by the broken lines 26a onFIG. 8, the dimensions being adjusted so that the tips, though blunt,still are in close wiping relationship with the inner walls of thehousing and with the edges of the matching paddle.

To continue the longitudinal advance of the material, in a more or lesshelical path, the long axes of each successive pair of paddles may beoffset, by an arcuate angle, from the long axes of the pair previouslyengaged by the material being treated. FIG. 11 (in which the arrowsindicate the direction of rotation of the shafts) illustrates variouspositions of the front faces of successive paddles, the paddledesignated as I being nearer to the discharge end of the machine thanthe other paddles; the paddle II being next, then the paddle III andthen the paddle IV which is furthest from the discharge end, there beinga 45 angle between the long axes of successive paddles. This offsettingof the long axes of adjacent paddles also aids in the mixing action ofthe apparatus. As will be seen from FIG. 11, when the paddles are in theposition designated as II, for example, their further movement acts tocompress the material between the edges of flanks of the paddles and thewalls of the housing, forcing the material into the paths of themovement of adjacent pairs of paddles.

The front and rear faces 32, 31 (FIGS. 9 and 10) of the paddles areadvantageously flat and, when the paddles are mounted on the shafts, aresituated in planes perpendicular to said shafts; the faces of adjacentpaddles are preferably close to each other; thus the clearance betweenthe front face of one paddle and the rear face of the next paddle may beon the order of about 0.03 inch. The clearances between the tips of thepaddles and the inner walls of the housing may be, for example, about0.03-0.04 inch; the clearances between the tip of the paddles and theedges of the paired paddles which they wipe may be about the same, e.g.about 0.0 3 inch.

It has been found advantageous to utilize, simultaneously, both theadvancing paddles (i.e. paddles whose front and rear faces are offset,as described previously) and the nonadvancing paddles (i.e. paddleswhose front and rear profiles are aligned, not offset).

In one typical arrangement, illustrated schematically in FIG. 2, after aseries of four full helices (on each shaft) of the feed screw elements13, there are a sequence of five pairs of advancing paddles (of thedimensions previously described) followed by one pair of otherwiseidentical non-advancing paddles, then three pairs of advancing paddles,this one-and-three arrangement being repeated three times more, followedby one pair of nonadvancing paddles and five pairs of advancing paddles.In this arrangement, the long axis of the front face of each paddle isoflfset 45 (in the direction of rotation of the shaft) from the longaxis of the front face of the next, downstream, paddle. Slightlyrearward of the end wall 34 of the housing is a rectangular horizontaldischarge tube 36 (see also FIG. 11), having an internal width of about2 inches, an internal height of about 1 inch and a length of about 6inches. This discharge tube is advantageously located at that side ofthe housing which corresponds to the side where the motion of the paddletip has a generally upward, rather than downward, component;alternatively, but less desirably, it may be located at the oppositeside, as indicated by the broken lines, at 36 (FIG. 11). While goodresults have been obtained with a discharge tube having a substantiallyuniform cross-section along its length, the discharge tube may betapered, narrowing toward its exit. In another discharge arrangement,found particularly suitable for the manufacture of lower density aerateddetergent laundry bars, the last pairs of paddles (adjacent thedischarge end) are not oifset 45 in the manner just described but are,instead, offset from each other (e.g. in the last five pairs of paddles,each pair may be offset 90 from its preceding and succeeding pair); thisarrangement has been found to give a highly aerated low density product,the air being injected under pressure into the device upstream of thedischarge end and through the lower half of the housing (eg at inlet 33,FIG. 2).

In another discharge arrangement, illustrated in FIGS. 12 and 13, thereis no side discharge tube. Instead, the processed detergent mixture isdischarged from the end of the device, e.g. through a dischargepassageway 38 in a plate 39 having circular holes 41 for receiving theparallel shafts 12. In one form which has been used with the paddlearrangement described in the preceding paragraph, the plate 39 is aboutone inch thick and the discharge passageway is horizontal andrectangular, being about 2 inches wide and about 1 inch high, the platebeing spaced, for example, about 1 to 6 inches from the ends 42, 43 ofthe upper and lower ridges 22, 23, the shape of the cavity in thehousing adjacent the plate 39 being a symmetrical oval formed by twospaced opposed vertical semi circles (of the same diameter and alignedwith the corresponding inner walls of the main cavity in the housing)joined by tangent horizontal lines. In the illustrated embodiment, theupper part of the discharge passageway 38 is about at the same level asthe top of the lower ridge 33 and the center of the discharge passagewayis offset about 10-15 from the center of the cavity in the housing. Itwill be noted that the discharge opening is at the right side of theapparatus, which (in contrast to the left side) is the side where themotion of the tips of the paddles has a generally upward component whenthe paddles are rotated on the direction shown by the arrows in FIG. 12.

In another discharge arrangement illustrated in FIG. 14, there are aseries of screw elements 46, identical with feed screw elements 13 atthe inlet end of the machine, mounted on the shafts 12. Discharge maytake place from a side discharge tube 47 shown in broken lines, but morepreferably from a discharge passageway 48 like that shown in FIG. 13 (orboth). The provision of the feed screw elements at the discharge endmakes it possible to obtain a much higher discharge pressure (e.g. onthe order of p.s.i.g.) which is particularly advantageous when themachine is used for making high-density detergent laundry bars at highrates of production.

In the overall arrangement shown schematically in FIG.

15, the extruded bar 51 continuously leaving the discharge tube 36 istaken up on moving endless belt 52, cooled and aged to harden it, passedthrough a conventional cutting device 53 and then pressed in aconventional soap bar press 54.

Typically, the extrusion opening may have an area of at least about twosquare inches and a height (equivalent to the thickness of theindividual bars) in the range of about to 3 inches, and a width of about2 inches or more. The width of the extrusion opening may be equal to thewidth of a single bar, or may be a multiple of that Width (e.g. two orthree times that width), in which case the extrudate may be cutlengthwise before or after it is fully cooled and hardened (e.g. bypulling or pushing it past one or more cutting elements, such as thinverticle wires, which may be heated to facilitate the cutting).

In the manufacture of the detergent laundry bar, there are employed asynthetic anionic detergent and a substantial proportion of awatersoluble solid builder salt, generally in excess of the amount ofsaid detergent.

The water-soluble anionic organic synthetic detergents which may bepresent in the compositions contain a sulfo acid solubilizing groupjoined (directly or indirectly through an intermediate linkage) to ahydrophobic organic group. Thus, such detergents include both organicsulfonates, e.g. R-SO compounds and organic sulfates, e.g. R-OSOcompounds, having sufficient water solubility to form detersive aqueoussolutions with foaming properties in concentrations which are suitablefor use in laundering operations. In the formula, R is a radical havingan aliphatic chain of at least six carbons, the radical preferablyhaving about 8-30 carbons. The detergents may be used in individually orin any desired combination.

Among the suitable water soluble anionic sulfonated detergents, thehigher alkyl aryl sulfonate detergents having about 8 to carbon atoms inthe alkyl group are particularly effective. It is preferred to use thehigher alkyl benzene sulfonate detergents for optimum effects, thoughother detergents containing a mononuclear aryl group, such as xylene,toluene, or phenol, may be used also. The higher alkyl substituent onthe aromatic nucleus may be branched or straight-chained in structure.Examples of straight chain alkyl groups are ndecyl, n-dodecyl andn-tetradecyl groups derived from natural fatty acids and petroleum.

Examples of branched chain alkyl derivatives are propylene and butylenepolymers such as propylene trimer, tetramer and pentamer. Examples ofother suitable water soluble anionic sulfonated detergents which may besatisfactorily used in the compositions of this invention are the alkanesulfonates containing about 8 to carbon atoms in the alkyl group and thealkyl sulfonates wherein the alkyl group of about 8 to 20 carbon atomsis linked to the sulfonic acid group through a --COOR group, e.g. oleicacid isothionate, -CONHR group, e.g. lauric acid taurate, or a OR group,e.g. dodecyl glyceryl ether sulfonate, wherein the R is a lower alkyl ora substituted lower alkyl group containing 2-3 carbon atoms.

Among the suitable water soluble organic sulfated detergents which it ispreferred to use in compositions of the invention are alkyl sulfates,e.g. sodium lauryl or coconut fatty alcohol sulfate, and the alkylethyleneoxy ether sulfates, e.g. sodium lauryl tri-ethyleneoxy sulfate,said alkyl groups having about 8 to 20 carbon atoms and the ethyleneoxysulfates containing about 1 to 15, preferably 2 to 10 moles of ethyleneoxide. The alkyl groups may be derived from naturally occurringglycerides or synthetically from petroleum, e.g. cracked waxes orethylene polymerization.

Other suitable organic sulfate detergents include sulfuric acid estersof polyhydric alcohols, incompletely esterified with higher fatty acids,e.g. coconut oil monoglyceride monosulfate, and sulfated higher alkylphenolethylene oxide condensates having an average of about 2 to 18moles of ethylene oxide per phenol group and about 6 to 18 carbons inthe alkyl group. The sulfated higher alkyl phenol-ethylene oxidecondensates which it is preferred to employ have about 4 to 6 moles ofethylene oxide per phenol group and about 8 to 12 carbon atoms in thealkyl group.

As previously indicated, these sulfate and sulfonate detergentsadvantageously are supplied to the shearing zone in acid liquid stateand are present in the final product in the form of their alkali metaland alkaline earth metal salts. The preferred alkali metals are sodiumand potassium and the preferred alkaline earth metals are calcium andmagnesium. Optimum effects are obtained with the sodium salts ingeneral.

The proportion of anionic organic detergent should be suitably selectedso as to yield a product having the desired performance and physicalcharacteristics. The detergent active functions as a foaming andcleansing agent as Well as a plasticizer in the compositions of theinvention. The proportion of said detergent will be minor compared tothe inorganic salts, usually in the range of about 10 to 40% by weight,and preferably about 15 to 30% by weight, of the finished bar.

The water soluble inorganic builder salts are known in the art generallyand may be any suitable alkali metal, alkaline earth metal, or heavymetal salt or combinations thereof. Ammonium or an ethanolammonium saltin a suitable amount may be added also, but generally, the sodium andpotassium salts or similar salts effective to add hardness or strengthto the bar are preferred. Examples are the water soluble sodium andpotassium phosphates, silicates, carbonates, bicarbonates, borates,sulfates and chlorides. The builder salts contribute detersiveefficiency when used in combination with sulfonic acid and/ or sulfuricester organic synthetic detergents. Particularly preferred builder saltsare the alkaline builder salts such as polyphosphates, silicates,borates, etc. Inasmuch as the builder effects and processingcharacteristics of the individual salts vary to some extent, generallymixtures of inorganic builder salts are used in variable, predominatingproportions, e.g. about 4585% by weight of the finished bar, preferablyin proportion of about 5065% by weight.

In the water soluble inorganic builder salt mixtures used in thedetergent laundry bar compositions, it is preferred to have present amixture of sodium tripolyphosphate and sodium or potassium bicarbonate.The combination or mixture of salts wherein the bicarbonate totripolyphosphate ratio is selected from the range of about 1:1 to about3:1, and which when admixed with the particular organic detergent andwater in proportions such that this mixture of inorganic salts is atleast about 40% of the total weight of the manufactured bar, results indesired processing effects and produce bars having superior physicalcharacteristics. Preferably, the proportions of this particularinorganic salt mixture is within the range of about 45 to about 65% byweight of the manufactured bar.

Both Phase I and Phase II sodium tripolyphosphate and mixtures thereofmay be successfully used in the cornpositions. The usual commercialtripolyphosphate consists mainly of the Phase II material. Thecommercial tripolyphosphate material is usually essentiallytripolyphosphate, e.g. 87-95%, with small amounts, e.g. 443% of otherphosphates, e.g. pyrophosphate and orthophosphate. Sodiumtripolyphosphate in its hydrated form may be used also. While trisodiumorthophosphate may be used in the amounts indicated, its presence oftenresults in a bar which tends to sweat in hot, humid climates and whosesurface tends to slough off more readily in such climates.

The sodium or potassium bicarbonate is an effective pH buffer and ispreferred because the particular tripolyphosphate bicarbonate mixtureresults in plastic detergent compositions which yield superior extrudedbars. This material is also desirable in that it is relativelyinexpensive,

has suitable solubility and does not cause frosting on the surface ofthe bar. The sodium bicarbonate may be incorporated directly asanhydrous bicarbonate or in the form of sesquicarbonate, a hydratecontaining both bicarbonate and carbonate.

Other suitable builder salts which may be incorporated in the builtsynthetic detergent bar compositions include the water soluble sodiumand potassium silicates, carbonates, borates, e.g. sodium tetraborate,chlorides and sulfates, e.g. magnesium sulfate. Generally, the totalproportion of these additional builder salts will be within the range offrom 0.5 to 24% by weight of the manufactured bar. The sodium andpotassium silicates having a Na O:SiO ratio within the range of 1:1 toabout 3.5 :1 are particularly effective as corrosion inhibitors inproportions of about 1 to 8% by weight of the finished bar. The sodiumsulfate content is advantageously kept low, e.g. below A, the weight ofthe phosphate (on an anhydrous basis); preferably, to avoid frosting,the sodium sulfate content is below about of the weight of the bar.

The final essential ingredient in the built synthetic detergent barcomposition is water or similar material. This component is generallypresent in a proportion within the range of about 2 to 30% by weight ofthe bar. This material serves as a plasticizer; also, when the anionicdetergent is formed in situ in the intensive shearing zone by reactionof injected liquid detergent acid (e.g. alkyl benzene sulfonic acid),the water helps promote the neutralization reaction. It will 'beappreciated that the total amount of water is the sum of the amountadded with the other ingredients in the feed (e.g. in the sulfonic acid,or with the salts, or separately) and the amount formed during theneutralization reaction. It is preferred that the water is from about 4%to 25% by weight.

Optionally, a fatty acid alkylolamide may be included in thecomposition. Such materials are generally condensation products ofhigher fatty acids having about to 14 carbon atoms in the acyl groupwith alkylolamides selected from the group consisting ofmono-ethanolamine, diethanolamine and isopropanolamine. Examples arelauric, capric, myristic and coconut monoethanolamide, diethanolamideand isopropanolamide. The alkylolamide suds builders may be present inproportions within the range of about 0 to 5%, preferably about 2%.

Various other ingredients may be included if desired. The compositionsmay beneficially include specific chelating agents capable of complexingiron such as the water soluble salts of ethylene diamine tetraaceticacid and the like. Other conventional auxiliary material which may beincorporated in the compositions are soil-suspending agents such assodium carboxymethylcellulose, tarnish inhibitors such as melamine,fluorescent brightening agents, perfumes, coloring agents, germicides orbacteriostats, skin-conditioning agents such as glycerine or lanolin,and the like. These materials may be admixed with the compositions inany suitable manner which does not substantially adversely affect theplasticity of the compositions.

Other ingredients which may be employed are starches (such as tapiocaflour, cornstarch, yucca starch or potato starch); the presence of thestarch aids in the processing of the mixture, improves its workabilityand appears to promote its flow over the inner walls of the bar-formingdie of the machine. Other agents which have related effects, and whichmay be added together with or in place of the starch, are clays such asbentonite and kaolin, which like starch tend to absorb moisture andswell to form gels in hot aqueous media, and finely divided cellulose(Solka-Floc). These additives may be included in amounts up to abouttheir eifects are marked above about 5% (e.g. 7%); a preferredproportion'is about 10-12% of starch. Starch also helps to give the bara brighter color.

Another processing aid is a wax such as paraffin, which may be added asfine flakes mixed with the builder salts or dissolved or dispersed inheated detergent sulfonic acid. Related waxy materials such aspetrolatum may also be used. The wax also helps to increase the life ofthe bar in ordinary use and to prevent sweating of the bar in certainclimates, when used in small amounts (e.g. to 1 /z%); smaller and largeramounts may be used as desired.

As previously indicated, the anionic detergent may be produced in situin the shearing zone. In this case, a stream of the liquid acidic formof the detergent and a stream of neutralizing agent (such as aqueousNaOH) may be injected continuously into the shearing zone;alternatively, the liquid neutralizing agent may be omitted andsufiicient solid neutralizing agent (e.g. finely divided alkali metalcarbonate and/or bicarbonate) may be included with the other solidingredients.

Further details relating to the composition and process for makingdetergent bars are found in the application of Austin and Lee, Ser. No.469,144, filed July 2, 1965, whose disclosure is incorporated herein byreference. The apparatus of this invention may also be used for makingother types of detergent products.

The following example is given to illustrate the invention further.

EXAMPLE In this example, the apparatus used was that of FIG. 14 havingan internal cavity about 3 feet long, the internal diameter of each ofthe intersecting circles being about 5 inches, the feed screw flights(two turns) extending about 4 inches in each shaft, the discharge screwflights (two turns) also extending about 4 inches on each shaft, thelong axes of the paddle faces being almost 5 inches long, and the shortaxes being 2 inches long, the paddles being about one inch thick, theoffset between long axes of successive paddles being 45, the pattern ofpaddles being: eight pairs of advancing paddles at the feed end,followed by two pairs of non-advancing paddles, two pairs of advancingpaddles, this and two-and-two arrangement being repeated three timesmore, then one pair of nonadvancing paddles and the 4 inches ofdischarge screw flights.

The discharge was effected through the off-center rectangular dischargepassageway previously described, spaced about 5 inches from the nearestpair of paddles. The speed of rotation of the co-rotating shafts wasabout 150 rpm. The rates of feed were 605 pounds per hour of the drymixture and 75 pounds per hour of water, which was injected continuouslyin the lower portion of the cavity at about 9 inches downstream of thefeed screw section. After a normalization period of about 15 minutes, asmooth bar was extruded continuously. The extruded material which, asextruded, had a temperature of about F., was permitted to cool, in aquiescent state, to room temperature and was then cut into individualbars and pressed at a pressure of about 200 p.s.i. The specific gravityof the bars was 1.5l.6. The dry mixture used in this example was afinely divided blend of 41% sodium tridecyl benzenesulfonate (branchedchain type, from sulfonation of a mixture of reaction products ofbenzene); 12% of tapioca flour, 24% sodium bicarbonate, 22% pentasodiumtripolyphosphate (commercial grade anhydrous) plus perfume and minorimpurities, which had been screened through a standard 40 mesh screen toremove lumps.

Numerous modifications and variations of the embodimerits of thisinvention can be made without departing from the spirit and scopethereof. Accordingly, it is to be understood that this invention is notto be limited except as defined in the appended claims.

What is claimed is:

1. Apparatus for the continuous mixing of solid and liquid material toform a pasty mass and for the continuous extrusion of said mass in theform of a bar of predetermined cross section, said apparatus comprisinga generally horizontal elongated housing, a pair of parallelsubstantially horizontal shafts symmetrically positioned with respect toan imaginary central plane, means for driving said shafts to rotate bothshafts in the same direction, said shafts having thereon a series ofpaired mixing and shearing projections arranged lengthwise of saidshafts and within said housing, said paired projections be ingconstructed and arranged so that, during the. rotation of said shafts,said projections wipe each others surfaces and the inside of saidhousing, said housing having adjacent one of its ends a feed opening forthe introduction of material to be mixed therein and having adjacent itsopposite end a discharge passageway for the extrusion of the mixed massin the form of a bar of predetermined cross section, said dischargepassageway being offset with respect to said central plane, saidprojections including pairs of paddles, each pair comprising a paddlemounted on one of said shafts and a cooperating and aligned paddlemounted on the other of said shafts, each paddle being elongated andhaving an arcuate edge profile and tips at opposite ends, the innerwalls of said housing conforming to the shape of concentric intersectingcircular cylinders centered on the axes of said shafts and of slightlygreater radius than the radial distance between the axis of thecorresponding shaft and the tip of the paddle thereon, said paddlesbeing constructed and arranged so that, during rotation of said shaftsand of the paddles carried thereby, the tip of each paired paddle wipessuccessively against the arcuate edge of the other paired paddle and theinner wall of the housing, said plane being vertical, said housinghaving an end wall, said discharge passageway being a generallyrectangular opening in said end Wall and being principally situatedwithin the imaginary circle constitutin a horizontal projection of thatone of said cylinders which houses those paddles whose tips move upwardalong the inner wall of the housing. ous extrusion of said mass in theform of a bar of prede 2. Apparatus for the continuous mixing of solidand liquid material to form a pasty mass and for the continuousextrusion of said mass in the form of a bar of predetermined crosssection, said apparatus comprising a generally horizontal elongatedhousing, a pair of parallel substantially horizontal shaftssymmetrically positioned with respect to an imaginary central plane,means for driving said shafts to rotate both shafts in the samedirection, said shafts having thereon a series of paired mixing andshearing projections arranged lengthwise of said shafts and within saidhousing, said paired projections being constructed and arranged so that,during the rotation of said shafts, said projections wipe each otherssurfaces and the inside of said housing, said housing having adjacentone of its ends a feed opening for the introduction of material to bemixed therein and having adjacent its opposite end a dischargepassageway for the extrusion of the mixed mass in the form of a bar ofpredetermined cross section, said discharge passageway being offset withrespect to said central plane, said projections including pairs ofpaddles, each pair comprising a paddle mounted on one of said shafts anda cooperating and aligned paddle mounted on the other of said shafts,each paddle being elongated and having an arcuate edge profile and tipsat opposite ends, the inner walls of said housing conforming to theshape of concentric intersecting circular cylinders centered on the axesof said shafts and of slightly greater radius than the radial distance.between the axis of the corresponding shaft and the tip of the paddlethereon, said paddles being constructed and arranged so that, during therotation of said shafts and of the paddles carried thereby, the tip ofeach paired paddle wipes successively against the arcuate edge of theother paired paddle and the inner wall of the housing, said dischargepassage-way being a tube leading from an inner wall of said housingalong a path transverse to said plane.

3. Apparatus as set forth in claim 2, said discharge passageway leadingfrom an inner wall of that one of said cylinders which houses thosepaddles whose tips move upward along the inner wall of the housing.

4. Apparatus for the continuous mixing of solid and liquid material toform a pasty mass and for the continuous extrusion of said mass in theform of a bar of predetermined cross section, said apparatus comprisinga gen erally horizontal elongated housing, a pair of parallelsubstantially horizontal shafts symmetrically positioned with respect toan imaginary central plane, means for driving said shafts to rotate bothshafts in the same direction, said shafts having thereon a series ofpaired mixing and shearing paddles arranged lengthwise of said shaftsand within said housing, each pair comprising a paddle mounted on one ofsaid shafts and a cooperating and aligned paddle mounted on the other ofsaid shafts, each paddle being elongated and having an arcuate. edgeprofile and tips at opposite ends, the inner walls of said housingconforming to the shape of concentric intersecting circular cylinderscentered on the axes of said shafts and of slightly greater radius thanthe radial distance between the axis of the corresponding shaft and thetip of the paddle thereon, said paddles being constructed and arrangedso that, during the rotation of said shafts and of the paddles carriedthereby, the tip of each paired paddle wipes successively against thearcuate edge of the other paired paddle and the. inner wall of thehousing, said housing having adjacent one of its ends a feed opening forthe introduction of material to be mixed therein and having adjacent itsopposite end a discharge passageway for the extrusion of the mixed massin the form of a bar of predetermined cross section, said shafts havingmounted thereon pairs of intermeshed helical screws mounted adjacentsaid opposite end to force the mixed mass through said dischargepassageway.

5. Apparatus as set forth in claim 4, said plane being vertical, saidhousing having an end wall, said discharge passageway being a generallyrectangular opening in said end wall and being principally situatedwithin the imaginary circle constituting a horizontal projection of thatone of said cylinders which houses those paddles whose tips move upwardalong the inner wall of the housing, said apparatus including conveyormeans for supporting the extruded bar as it leaves said opening andcutter means for subdividing said bar into individual laundry bars.

6. Apparatus for the continuous mixing of solid and liquid material toform a pasty mass and for the continuous extrusion of said mass in theform of a bar of predetermined cross section, said apparatus comprisinga generally horizontal elongated housing, a pair of parallelsubstantially horizontal shafts symmetrically positioned with respect toan imaginary central plane, means for driving said shafts to rotate bothshafts in the same direction, said shafts having thereon a series ofpaired mixing and shearing projections arranged lengthwise of saidshafts and within said housing, said paired projections beingconstructed and arranged so that, during the rotation of said shafts,said projections wipe each others surfaces and the inside of saidhousing, said housing having adjacent one of its ends a feed opening forthe. introduction of material to be mixed therein and having adjacentits opposite end a discharge passageway for the extrusion of the. mixedmass in the form of a bar of predetermined cross section, said dischargepassageway being offset with respect to said central plane, saidprojections including pairs of paddles, each pair comprising a paddlemounted on one of said shafts and a cooperating and aligned paddlemounted on the other of said shafts, each paddle being elongted andhaving an arcuate edge profile and tips at opposite ends, the innerwalls of said housing conforming to the shape of concentric intersectingcircular cylinders centered on the axes of said shafts and of slightlygreater radius than the radial distance between the axis of thecorresponding shaft and the tip of the paddle thereon, said paddlesbeing constructed and arranged so that, during the rotation of saidshafts and of the paddles carried thereby, the tip of each paired paddlewipes successively against the arcuate edge of the other paired paddleand the inner wall of the housing, the two paddles of each pair being ofsubstantially the same size and shape, each paddle having twodiametrically opposed tips joined by tWo convex arcs intersectingequiradial circles, the long axis joining the tips of each paired paddlebeing at right angles to the corresponding long axis of the other paddleof each pair, each paddle having a front face and a rear face, both saidfaces being in planes transverse to said central plane, the front faceand rear face of some of said paddles being aligned in a directionparallel to the shafts and the. front face and rear face of others ofsaid paddles being offset by an acute angle about the respective shaftson which the paddles are mounted, the construction and arrangement ofsaid offset-faced paddles being such as to advance the material beingprocessed in said housing in a direction toward the discharge. end ofsaid housing.

7. Apparatus for the continuous mixing of solid and liquid material toform a pasty mass and for the continous extrusion of said mass in theform of a bar of predetermined cross section, said apparatus comprisinga generally horizontal elongated housing, a pair of parallelsubstantially horizontal shafts, means for driving said shafts to rotateboth shafts in the same direction, said shafts having thereon a seriesof paired mixing and shearing projections arranged lengthwise of saidshafts and Within said housing, said projections including pairs ofpaddles, each pair comprising a paddle mounted on one of said shafts anda cooperating and aligned paddle. mounted on the other of said shafts,each paddle being elongated and having an arcuate edge profile and tipsat opposite ends, the inner Walls of said housing conforming to theshape of concentric intersecting circular cylinders centered on the axesof said shafts and of slightly greater radius than the radial distancebetween the axis of the corresponding shaft and the tip of the paddlethereon, said paddles being constructed and arranged so that, during therotation of said shafts and of the paddles carried thereby, the tip ofeach paired paddle wipes successively against the arcuate edge of theother paired paddle and the inner wall of the housing, said housinghaving adjacent one of its ends a feed opening for the introduction ofmaterial to be mixed therein and having adjacent its opposite end adischarge passageway for the extrusion of the mixed mass in the form ofa bar of predetermined cross section, said discharge passageway leadingfrom an inner wall of the housing along a path transverse to saidshafts.

References Cited UNITED STATES PATENTS 2,584,225 2/1952 Plunguian et a1.2,689,962 1/1955 Swalloin. 3,146,493 9/1964 Steinle et a1.

FOREIGN PATENTS 966,424 8/1967 Great Britain.

WILLIAM J. STEPHENSON, Primary Examiner US. Cl. X.R. 18l2

